Conditional love? Co‐occurrence patterns of drought‐sensitive species in European grasslands are consistent with the stress‐gradient hypothesis

Abstract

Aim The stress‐gradient hypothesis (SGH) postulates that species interactions shift from negative to positive with increasing abiotic stress. Interactions between species are increasingly being recognized as important drivers of species distributions, but it is still unclear whether stress‐induced changes in interactions affect continental‐to‐global scale species distributions. Here, we tested whether associations of vascular plant species in dry grasslands in Europe follow the SGH along a climatic water deficit (CWD) gradient across the continent. Location Dry grasslands in Europe. Time period Present. Major taxa studied Vascular plants. Methods We built a context‐dependent joint species distribution model (JSDM) to estimate the residual associations (i.e., associations that are not explained by the abiotic environment) of 161 plant species as a function of the CWD based on community data from 8,660 vegetation plots. We evaluated changes in residual associations between species for pairs and on the community level, and we compared responses for groups of species with different drought tolerances. Results We found contrasting shifts in associations for drought‐sensitive and drought‐tolerant species. For drought‐sensitive species, 21% of the pairwise associations became more positive with increasing CWD, whereas 17% became more negative. In contrast, only 17% of the pairwise associations involving drought‐tolerant species became more positive, whereas 27% became more negative in areas with a high CWD. Additionally, the incidence of positive associations increased with drought for drought‐sensitive species and decreased for drought‐tolerant species. Main conclusions We found that associations of drought‐sensitive plant species became more positive with drought, in line with the SGH. In contrast, associations of drought‐tolerant species became more negative. Additionally, changes in associations of single species pairs were highly variable. Our results indicate that stress‐modulated species associations might influence the distribution of species over large geographical extents, thus leading to unexpected responses under climate change through shifts in species associations.

Refining the stress gradient hypothesis for mixed species groups of African mammals

“…More generally, differences in species-specific grouping propensities (Fig. 2 ) indicate strong context dependence when assessing the impact of environmental variables on community structure and underscore the importance of choosing a species’ lens for disentangling relationships between grouping patterns of multiple organisms and environmental gradients 48 , 49 . Not accounting for species identity could bias relationships between grouping patterns and environmental variables (Fig.…”

Human disturbance increases spatiotemporal associations among mountain forest terrestrial mammal species

“…Interspecific spatial associations can arise from species interaction, response to environmental covariates, and common dispersal barriers ( Blanchet et al, 2020 ; de Jonge et al, 2021 ; Poggiato et al, 2021 ). Our context-dependent JSDM, which accounts for similarities and disparities in species-specific response to habitat covariates considered relevant to medium- and large-bodied mammal species, detected a higher prevalence of interspecific spatial associations in human-disturbed habitats.…”

Incorporating Species-Conditional Co-Occurrence When Selecting Indicator Species to Monitor Restoration after Mangrove Removal from the Siangshan Wetland, Taiwan

“…When a clear community mechanism is analyzed, it is conducive to policy formulation at the current stage and future maintenance and management. Melinda et al (2021) [24] found that the interaction between species is increasingly recognized as an important driving factor for the distribution of species, but it is not clear whether changes in the interaction caused by pressure will affect the distribution of species [23].…”